Move some Document timers to frame-specific task runners.

third_party/WebKit/Source/core/frame/FrameTimer.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FrameTimer_h
+#define FrameTimer_h
+
+#include "core/dom/TaskRunnerHelper.h"
+#include "platform/Timer.h"
+
+namespace blink {
+
+template <typename TimerFiredClass>
+class FrameTimer : public TaskRunnerTimer<TimerFiredClass> {

[haraken, 2016/10/19 03:07:47]

What's your plan in the end? Are you planning to mix FrameTimers and
TaskRunnerTimers in the code base? Or are you planning to minimize # of
TaskRunnerTimers?

[dcheng, 2016/10/19 03:47:44]

The idea for FrameTimer is to make it easy to see when something is associated
with a frame's task queue. It's possible to tell with
TaskRunnerTimer(TaskRunnerHelper::get(...), ...) but it's a little harder to
search for.

Since we want to associate as many things with per-frame queues as possible,
that means we will probably end up trying to minimize the number of
TaskRunnerTimers.

That being said, if we're planning on replacing this with postCancellableTask...
maybe there's not much value to doing this and we should just use
TaskRunnerTimer directly?

[haraken, 2016/10/19 09:07:12]

Yeah, I'd prefer not mixing postCancellableTask, FrameTimer and TaskRunnerTimer
in the code base.

Will the following work?

- postCancellableTask for all one-shot timers
- TaskRunnerTimer for other timers

+ public:
+  using TimerFiredFunction =
+      typename TaskRunnerTimer<TimerFiredClass>::TimerFiredFunction;
+
+  FrameTimer(TaskType taskType,
+             Document* document,

[dcheng, 2016/10/19 00:08:39]

I'll add additional overloads as needed?

[haraken, 2016/10/19 03:07:48]

Sure.

ExecutionContext* might be better since workers will also use FrameTimers.

[dcheng, 2016/10/19 03:47:44]

Done.

+             TimerFiredClass* timerFiredClass,
+             TimerFiredFunction timerFiredFunction)
+      : TaskRunnerTimer<TimerFiredClass>(
+            TaskRunnerHelper::get(taskType, document),
+            timerFiredClass,
+            timerFiredFunction) {}
+};
+
+}  // namespace blink
+
+#endif  // FrameTimer_h